Data Allocation

Question 1

pointer

Answer 1

variable that holds a memory address, rather than holding data. Indicated by a *

don’t declare multiple pointers on one line

must be declared to another variable of same type, not just to a value

Question 2

pointer’s reference operator

Answer 2

&, obtains variable’s address

Question 3

dereference operator

Answer 3

prepended to a pointer’s variable name to retrieve that data to which the pointer variable points

*valPointer = 10; // changes someInt to 10

Question 4

NULL means

Answer 4

nothing

when checking if a pointer is NULL, only use the value; don’t use a deference pointer

Question 5

Syntax errors

Answer 5

Occurs when there is an error in the code that prevents the program from compiling

Question 6

Runtime Error

Answer 6

Program is running but encounters an issue with data, that compiler couldn’t predict during compilation

Question 7

calloc

Answer 7

allocates a block of memory for an array of elements, initializing all bits in the allocated memory to zero

Question 8

malloc(bytes)

Answer 8

specifies the number of bytes to allocate in a memory. found in stdlib.h library. returns a void pointer of memory address to the memory location. returns null if function failed to allocate memory (all memory is used up)

(double*)malloc(sizeof(double));
The double above converts the call from a void to a double returner, but not necessary because it automatically does this in C.

Question 9

how many bits in an int?

Answer 9

32 bits, 4 bytes

Question 10

free(pointerVariable)

Answer 10

deallocates a memory block pointed to by a given poitner=

Question 11

Memory Leak

Answer 11

Occurs when a program allocates memory but loses the ability to access the allocated memory.

Question 12

Garbage collection

Answer 12

Automatic process of finding and freeing unreachable allocated memory locations

Question 13

Unusable Memory

Answer 13

Memory locations that have been dynamically allocated but can no longer be used by a program.

Question 14

strchr(sourceStr, searchChar)

Answer 14

Returns NULL if searchChar does not exist in sourceStr, Else, returns pointer to first occurrence

Question 15

strrchr(sourceStr, searchChar)

Answer 15

Returns NULL is searchChar does not exist in sourceStr. Else, returns poitner to LAST occurrence (searches in reverse)

Question 16

strstr(str1, str2)

Answer 16

Returns NULL if str2 does not exist in str1. Else, returns a char pointer pointing to the first character of the first occurrence of string str2 within string str1.

Question 17

Dynamically Allocated Array

Answer 17

determining the total number of bytes needed to store the desired number of elements, using the following form:

pointerVariableName = (dataType*)malloc(numElements * sizeof(dataType))

Question 18

Statically allocated array

Answer 18

declare arrays to have a fixed size

Question 19

fgets

Answer 19

name, size, how (stdin)

Question 20

strcat

Answer 20

concatenates the string at the end of a given array

Question 21

1 byte = x bits

Answer 21

8 bits (wide), which is the amount of data stored at a single address

Question 22

True or False: In this example, the scalar variables were arranged in memory in the order in which they were declared

Answer 22

False

Question 23

True or False: Scalar variables of the same data type were packed together.

Answer 23

True

Question 24

True or False: For each of the two array variables, the first element is adjacent to the second element in memory

Answer 24

True

Question 25

True or False: The result of incrementing an int pointer by 1 is the next sequential address in memory.

Answer 25

False. Adding 1 to a pointer variable increments it by the size of the variable type, so that it points to the next consecutive value of that type. Since an int is 4 bytes, it takes 4 consecutive addresses to store an int, so incrementing an int pointer by 1 adds 4 to the address.

Question 26

Code

Answer 26

The region where the program instructions are stored

Question 27

Static Memory

Answer 27

The region where global variables (variables declared outside any function) as well as static local variables (variables declared inside functions starting with the keyword "static") are allocated. Static variables are allocated once and stay in the same memory location for the duration of a program's execution

Question 28

The Stack

Answer 28

The region where a function's local variables are allocated during a function call. A function call adds local variables to the stack, and a return removes them, like adding and removing dishes from a pile. Because this memory is also automatically allocated and deallocated, it is also called automatic memory. All non-static, local variables inside functions are located on the stack.

Question 29

pass by pointer / pass by reference

Answer 29

used to return two values, by putting a * before a parameter name and & before the corresponding argument variable

Question 30

(*structPtr).membername is equivalent to

Answer 30

structPtr->membername;

Question 31

True or False: Like Python, C has a garbage collector that automatically frees dynamically allocated memory when it is no longer referenced in the program.

Answer 31

False. In C programs, dynamically allocated memory must be explicitly deallocated using the free library call.

Question 32

True or False: Static variables are called "static" because their values can't be reassigned

Answer 32

False. Static variables can be assigned new values and retain their values between function calls.

Question 33

Number of Bytes a char stores:

Answer 33

1

Question 34

number of bytes for an ip address

Answer 34

8

Question 35

number of bytes for string

Answer 35

1*N

Question 36

Pointer to a variable goes into the....

Answer 36

heap

Question 37

number of bytes for char pointer

Answer 37

4 bytes

Question 38

purpose of sizeof()

Answer 38

counts number of bytes

Question 39

number of bytes in a double

Answer 39

8